readwritelock subcommand for dbx: Display a list of active read/write lock objects

Format

readwritelock [number …]
readwritelock lock
readwritelock unlock
readwritelock holder
readwrite noholder

Description

The readwritelock subcommand displays a list of active read/write lock objects for the application program. All active read/write lock objects are listed unless you use the number parameter to specify the read/write lock objects you want listed. You can also select only locked or unlocked read/write locks, or read/write locks with or without holders, by using the lock, unlock, holder, or noholder options.

In order to capture the read/write lock variables, dbx must be debugging your program before the read/write lock variable is created. You must have coded your application in one of the following ways:

Add the following line at the top of the C program:
```
#pragma runopts(TEST(ALL))
```
Or:
Code an assembler program, CEEUOPT, to invoke the CEEXOPT macro, which specifies TEST(ALL). For examples of how to code this program, see z/OS Language Environment Programming Guide.
Or:
Specify test(all) in the _CEE_RUNOPTS environment variable:
```
export _CEE_RUNOPTS="test(all)"
```

Usage notes

The readwritelock subcommand can be run only while the dbx debug program is running.

Examples

To display all read/write lock objects, enter:
```
readwritelock
```
To display read/write lock objects number 1 and number 4, enter:
```
readwritelock 1 4
```
To display all locked read/write lock objects, enter:
```
readwritelock lock
```
To display all unlocked read/write lock objects, enter:
```
readwritelock unlock
```
To display all read/write lock objects with holders, enter:
```
readwritelock holder
```
To display all read/write lock objects without holders, enter:
```
mutex noholders
```